B. Equipment and Technique 



By John D. Lattin 



Oregon State College, Corvallis 



Field work in aquatic entomology is carried out by 

 many persons with diverse points of view. Some 

 approach the subject as taxonomists specializing 

 in one or another of the groups of aquatic insects; 

 others are primarily interested in life histories or 

 ecological relations. And there is an increasing 

 number of professional workers whose primary concern 

 is quantitative sampling of populations for mosquito 

 control or stream and lake management. It is the 

 object of this chapter to describe the equipment and 

 methods best suited to each of these varied purposes. 

 A fuller discussion of entomological equipment is 

 given in Peterson (1953), culture methods are de- 

 scribed in the compendium edited by J. G. Needham 

 (1937), and general limnological methods are treated 

 in detail in Welch (1948). 



GENERAL COLLECTING 



Terrestrial 



Most aquatic insects are terrestrial or aerial as adults 

 and can be identified to the species level only at 

 this stage. Therefore it is important to collect gener- 

 ally in the vicinity of water where adult insects 

 are most likely to occur. Stones, boards, and piles 



drill ',!" holes W apart 



Intro, fig. 66. Specifications for construction of insect 

 net (Ross, 1953). 



of debris should be turned over and carefully exam- 

 ined. All types of vegetation growing near the water 

 should be examined and the insects dislodged by 

 beating or "sweeping" into a net. Swarms of gnats 

 and other aerial insects should be swept with the net. 

 Nets.— Although many different types of nets are 

 used by collectors, the basic design is the same 

 (intro. fig. 66). A light, strong handle is used with 

 a ring of stout, spring-steel wire to which is fastened 

 a bag of nylon netting. Aerial nets, for catching 

 insects in flight, should be light enough to handle 

 easily. The sweeping net, on the other hand, is of 



Intro, fig. 67. Sweeping net in action (Ross, 1953). 



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